Previous studies have shown that adult AIDS patients have increased rates of whole body protein turnover (WBPT), and that proteolysis is postively correlated with viral load. The hypothesis is that WBPT is high in pediatric AIDS patients. Protease inhibitors (PI) lower viral burden and may increase lean body mass. The hypothesis is that PIs improve lean body mass, in part by decreasing proteolysis. We will measure lean body mass, WBPT, & viral load in 10 pediatric AIDS subjects before & after 6 weeks of PI therapy, and compare to healthy controls. To date the investigators have analyzed data from 3 HIV+ positive and 7 controls. HIV+ patients have increased proteolysis compared to controls. After six weeks of protease inhibitor therapy, proteolysis decreases, but not to the level of controls.